RU2549064C2 - Smoke filtration - Google Patents

Abstract

FIELD: tobacco industry.

SUBSTANCE: invention refers to a smoking material containing dry carbon gel representing xerogel, aerogel and/or cryogel.

EFFECT: providing smoke filtration.

13 cl, 4 dwg, 7 tbl, 14 ex

Description

Field of Invention

The present invention relates to a new use of a specific type of porous coal material for filtering smoke in smoking articles.

Uroen technology

Filtration is used to reduce the level of certain particulate matter and / or vapor-phase components of tobacco smoke inhaled by smoking. It is important that this is achieved without removing significant levels of other components, such as organoleptic components, and thereby without compromising the quality or flavor of this product.

Cigarette filters often consist of cellulose acetate fibers that mechanically filter aerosol particles. It is also known to introduce into the filters porous carbon materials (dispersed in cellulose acetate fibers or in the filter cavity) for adsorption of some components of the smoke, usually physical adsorption. Such porous carbon materials are made from carbonated forms of many different organic materials, most often plant-based, such as coconut shells. However, synthetic polymers are also carbonized to produce porous coals. In addition, fine coal particles are sintered with binders to produce porous coals by the method disclosed in US 3351071.

A great influence on the properties of porous carbon material is exerted by the high-precision method used in its manufacture. Therefore, it is possible to obtain coal particles having a wide range of shapes, sizes, size distributions, pore volumes, pore size distributions and surface areas, each of these indicators affecting their effectiveness as adsorbents. Also an important variable is the rate of attrition; low abrasion rates are preferred to avoid dust formation during high-speed filter manufacturing.

In general, porous coals having a high surface area and a large total pore volume are required to maximize adsorption. However, these indicators must be balanced with a low attrition rate. The surface area and total pore volume of traditional materials, such as coconut charcoal, are limited by their relative brittleness. In addition, the possibility of introducing a significant part of the meso- and macropores is limited by the strength of the material. As Adsorption (2008) 14, 335-341 explains, traditional coconut charcoal is essentially microporous, and an increase in the activation time of coal leads to an increase in the number of micropores and surface area, but not to an actual change in pore size or distribution. Thus, as a rule, it is impossible to obtain coal from coconuts containing a significant number of meso- or macropores.

Another factor to consider is that the residence time of smoke in a typical 27 mm cigarette filter with standard resin measurements is of the order of milliseconds. Thus, porous carbon materials for smoke filtration must be optimized so that they are highly efficient adsorbents for such a short period of time.

In light of the foregoing, it still seems possible to improve in this area with respect to the use of porous carbon materials for filtering smoke.

SUMMARY OF THE INVENTION

In a first aspect of the invention, there is provided a smoking article comprising a carbon dry gel.

In a second aspect of the invention, there is provided a filter for use in a smoking article comprising a carbon dry gel.

In a third aspect of the invention, the use of carbon dry gel for filtering smoke is provided.

Brief Description of the Drawings

For a more complete understanding of the invention, embodiments of the invention will be described using an illustrative example with reference to the accompanying drawings, in which:

figure 1 shows the particles of dry carbon gel distributed over the entire length of the cigarette filter,

figure 2 shows the particles of carbon dry gel placed in the cavity of a cigarette filter,

figure 3 shows a cigarette having a sticker on the filter containing carbon dry gel particles,

4 shows a nitrogen adsorption isotherm for a carbon dry gel according to the invention.

Detailed Description of the Invention

In the present invention uses carbon dry gel. Such dry gels are porous materials in a solid state, which are obtained from gels or sol gels, the liquid component of which is removed and replaced by gas, followed by pyrolysis / carbonization. These gels can be classified according to the drying method, they include carbon xerogels, aerogels and cryogels. Similar types of materials are known.

Xerogels, as a rule, are formed when using the stage of evaporative drying under ambient pressure. They usually have a monolithic internal structure, similar to a rigid foam with a low density, containing, for example, 60-90 vol.% Air. Aerogels, on the other hand, are obtained using other methods, for example, drying under supercritical conditions. They are characterized by less shrinkage than xerogels at the drying stage and thus lower density (for example, 90-99 vol.% Air). Cryogels are obtained by lyophilization.

Preferably, the dry gel of the invention is a carbon xerogel or carbon aerogel, preferably a carbon xerogel.

Dry gels used in the present invention can be obtained from any source. There are several methods for preparing the gel to be dried. In an embodiment of the invention, the gel is prepared by aqueous polycondensation of an aromatic alcohol (preferably resorcinol) with an aldehyde (preferably formaldehyde). In an embodiment of the invention, sodium carbonate is used as a catalyst. An illustrative method is described in Chem. Mater. (2004) 16, 5676-5681.

The first stage of obtaining dry carbon gels used in the present invention is the formation of polycondensate by polycondensation of aldehyde and aromatic alcohol. Commercially available polycondensate can be used.

The starting material for the production of the polycondensate can be an aromatic alcohol, such as phenol, resorcinol, catechin, hydroquinone and phloroglucinol, and an aldehyde such as formaldehyde, glyoxal, glutaraldehyde or furfural. A commonly used and preferred reaction mixture includes resorcinol (1,3-dihydroxybenzene) and formaldehyde, which react with each other in an alkaline environment to form a gel-like polycondensate. The polycondensation process is usually carried out in an aqueous environment. Suitable catalysts are (water soluble) alkaline salts such as sodium carbonate, as well as inorganic acids such as trifluoroacetic acid. To obtain a polycondensate, the reaction mixture is heated. Typically, the polycondensation reaction is carried out at a temperature above room temperature, preferably from 40 to 90 ° C.

The rate of polycondensation reaction, as well as the degree of crosslinking in the resulting gel can be affected, for example, by the relative amounts of alcohol and catalyst. One skilled in the art knows how to control the amounts of these compounds to achieve the desired result.

The resulting polycondensate can be further processed without prior drying. In a possible alternative embodiment, it is dried to partially or completely remove water. However, it has been shown that it is preferable not to completely remove the water.

It was shown that to obtain particles of the desired size, it is preferable to reduce the particle size of the polycondensate before further processing. The reduction of the particle size of the polycondensate is carried out using traditional methods of mechanical grinding of particles or grinding. Preferably, the size reduction step results in the formation of granules with the desired size distribution, whereby the formation of a powder fraction could be substantially avoided.

Then the polycondensate (particle size of which is optionally reduced) is subjected to pyrolysis. Pyrolysis can also be called carbonization. During the pyrolysis, the polycondensate is heated to a temperature of from 300 to 1500 ° C, preferably from 700 to 1000 ° C. During pyrolysis, a porous coal xerogel with a low density is formed.

One way to influence the properties of a coal xerogel, for example, pore volume, surface area and / or pore volume distribution, is to treat the polycondensate before, during or after pyrolysis with steam, air, CO ₂ , oxygen or a gas mixture that can be diluted with nitrogen or other inert gas. In particular, it is preferable to use a mixture of nitrogen and steam.

Advantageously, the dry gels of the invention are very hard and strong; accordingly, their abrasion rate is low and the pore structure can be controlled more simply without fear of destroying the material. In addition, since ordinary coals are black, the dry gels of the invention have a transparent and shiny appearance, for example, a shiny black appearance.

The dry gels of the invention may be of any suitable shape, for example, the shape of particles, fibers, or a monolithic whole. However, it is preferred that they are in the form of particles. Suitable particle sizes are 100-1500 microns or 150-1400 microns.

The carbonization step is preferably carried out in a gaseous atmosphere comprising nitrogen, water and / or carbon dioxide. In other words, the dry gels used in the present invention may be inactive or, in some embodiments, activated, for example, with steam or carbon dioxide. Activation is preferred to provide improved pore structure.

Dry gels are introduced into a cigarette filter or smoking article using conventional methods. As used herein, the term “smoking article” includes tobacco products, such as cigarettes, cigars and cigarillos, based on tobacco, tobacco derivatives, exploded tobacco, reconstituted tobacco or tobacco substitutes, as well as smoldering but non-burning products. Preferred smoking articles of the invention are cigarettes. The smoking article is preferably provided with a filter for the gaseous stream drawn in by the smoker, preferably a dry gel is introduced into this filter, but alternatively or in addition it is included in another part of the smoking article, such as in or on cigarette paper, or in the filler material tobacco products.

The cigarette filter of the invention may take the form of a filter mouthpiece for insertion into a smoking article, or any suitable structure. For example, with reference to FIG. 1, a filter (2) for a cigarette (1) may comprise a carbon dry gel (3) uniformly distributed throughout the filter material of the filter, such as cellulose acetate. Alternatively, the filter may be in the form of a "Dalmatian" filter with dry gel particles distributed over the entire fiber segment at one edge of the filter, which will be the edge of the tobacco tow when introduced into the cigarette.

Another embodiment of the invention with reference to FIG. 2 is the manufacture of a filter in the form of a “cavity” filter comprising several segments, wherein the dry gel (3) is enclosed in one cavity (4). For example, a cavity containing a dry gel may be between two segments of a fibrous filter material.

Alternatively, with reference to FIG. 3, the dry gel (3) may be placed on the filter swab wrapper (5), preferably on its radial inner surface. This is achieved in the usual way (see GB 2260477, GB 2261152 and WO 2007/104908), for example by applying a sticker to the wrapper and spraying dry gel material onto the sticker.

Another option is to provide a dry gel adhered to a thread (eg, cotton thread) passed along the filter in a known manner.

Other possibilities are well known to those skilled in the art.

Any suitable amount of dry gel may be used. However, it is preferable to introduce at least 10 mg, at least 25 mg, or at least 30 mg of a dry gel into the filter or smoking article.

For filtering tobacco smoke, it is preferable to use a porous carbon material having a number of different pore sizes in order to adsorb a number of different compounds contained in the smoke. The different pore sizes found in coal materials are classified as follows according to the IUPAC definition: micropores have a diameter of less than 2 nm, mesopores have a diameter of 2-50 nm and macropores have a diameter of more than 50 nm. The relative volumes of micropores, mesopores and macropores are estimated using known methods based on nitrogen adsorption and mercury porosimetry, the former mainly for micro- and mesopores and the latter, mainly for meso- and macropores. However, since the theoretical basis for these estimates is different, the values obtained by both methods cannot be directly compared with each other.

In the present invention, it has been found that a particular group of carbonaceous dry gels demonstrates additional advantages over coconut charcoal with respect to reducing the level of vapor-phase smoke analytes. Specifically, coal-based dry gels with a total pore volume (measured by nitrogen adsorption) of at least 0.5 cm ³ / g, of which at least 0.1 cm ³ / g are mesopores, have better performance than charcoal from coconuts . In this regard, the high surface area by BET (BET) is not significant.

Preferably, the total pore volume (measured by nitrogen adsorption) is at least 0.5, 0.6, 0.7, 0.80, 0.85, 0.87, 0.89, 0.95, 0.98, 1 , 00, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2 , 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0 or 3.1 cm ³ / g.

Preferably at least 0.1, 0.2, 0.3, 0.4, 0.5, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0, 85, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, Mesopores (2.1, 2.2, 2.3, 2.4 or 2.4 cm ³ / g of the total pore volume) (measured by nitrogen adsorption using the BJH analysis (pore distribution by the Barrett-Joyner-Hallenda method) on the isotherm desorption curve nitrogen).

Preferably, at least 0.05, 0.10, 0.15, 0.2, 0.3, 0.4, 0.5, 0.6 or 0.7 cm ³ / g of the total pore volume is micropores (measured by nitrogen adsorption isotherm). In one embodiment, at least 0.4 cm ³ / g of the total pore volume is micropores.

Preferably, the total volume of mesopores is greater than the total volume of micropores.

In an embodiment of the invention, dry gels have a pore size distribution (measured by nitrogen adsorption) in the range of 15 to 45 nm, preferably in the range of 20 to 40 nm.

In one embodiment, the dry carbon gels of the invention have relatively large micropores and mesopores, i.e., mesopores have a pore size (diameter) of at least 10 nm and preferably at least 20 nm (i.e., mesopores have a pore size 20-50 nm).

The desired ratio of micropores to mesopores is at least 1: 2, preferably at least 1: 3.

In an embodiment of the invention, the BET surface area is at least 500, 550, 600, 650, 750, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800 or 1900 m ² / g.

The invention is illustrated by the following examples.

Example 1. Synthesis of xerogel

Coal xerogel samples were prepared by drying the resorcinol / formaldehyde polymer under ambient pressure in accordance with the general process set forth in Chem. Mater. (2004) 16, 5676-5681 (where the material obtained is incorrectly called airgel).

Resorcinol (Fluka®, puriss. (98.5% purity)), formaldehyde (Fluka®, 37% in water, stabilized with methanol) and sodium carbonate (Fluka®, anhydrous, 99.5%) were dissolved as a catalyst in deionized water while stirring with a magnetic bar to obtain a homogeneous solution. After thermal curing for one day at room temperature, one day at 50 ° C and three days at 90 ° C, wet gels were added to acetone and left for three days at room temperature (using fresh acetone daily) to replace water inside the pores. Then, the samples were dried at room temperature under atmospheric pressure and pyrolyzed at temperatures up to 800 ° C (4 ° / min, 10 minutes at 800 ° C) in an argon atmosphere, thus converting to carbon xerogels.

Different samples were obtained by changing the concentration of the catalyst and the content of the reactant, as shown in the table below. Resorcinol and formaldehyde were used in a 1: 2 molar ratio (which corresponds to reaction stoichiometry).

Table Try The percentage of resorcinol and formaldehyde The molar ratio of resorcinol: sodium carbonate Xerogel 1 twenty 200: 1 Xerogel 4 fifty 1000: 1 Xerogel 6 40 500: 1 Xerogel 5 thirty 500: 1 Xerogel 2 fifty 500: 1

All these xerogels took the form of transparent black granules.

Example 2. Properties of the xerogel

Adsorption isotherms were constructed at 77K for the coals shown in Example 1, and BJH analyzes of desorption curves were performed to calculate pore sizes and size distributions. The surface area of the samples was also measured. As a control, microporous steam-activated coconut charcoal (Ecosorb®CX from Jacobi Carbons) was investigated. The results are presented in the table below.

Table Try Surface Area ^* (m ² / g) Total pore volume (cm ³ / g) ** The pore volume in micropores (cm ³ / g) Pore volume in mesopores (cm ³ / g) Mesopore pore size range (nm) Pore sizes with a maximum in the size range of mesopores (nm) Ecosorb® CX 1000 0.50 0.50 0 - - Xerogel 1 Xerogel 4 Xerogel 6 650 0.38 0.17 0.21 3-5 four Xerogel 5 690 1,04 0.19 0.85 5-25 eleven Xerogel 2 680 0.89 0.19 0.70 4-22 10 * Surface areas were measured using absorption at a relative pressure of P / P ₀ 0.2. ** Estimated by the amount of adsorbed N ₂ at a relative pressure P / P _{0 of} 0.98.

Example 3. Filter characteristics

A standard-design cigarette was proposed (56 mm tobacco tow, 26.4 mm circumference, modified Virginia mixture, 27 mm filter), the filter had a cavity, on both sides limited by a segment of cellulose acetate. 60 mg of Xerogel 1 obtained in example 1 was weighed into the filter cavity. Other cigarettes were prepared in the same way, each containing one of the samples of xerogel or coconut charcoal. A cigarette having an empty cavity with the same dimensions was used as a control. After preparation, the cigarettes were aged at 22 ° C. and 60% relative humidity for about three weeks before smoking.

Cigarettes were smoked in accordance with ISO conditions, i.e. 35 ml puff for 2 seconds every minute, and the levels of tar, nicotine, water and carbon monoxide in the smoke were determined. The results are presented in the table below.

Table Charcoal in the filter Puff, number (per sig) NFDPM (m g / s and g) Nicotine (mg / sig) Water (mg / sig) CO (mg / sig) Absent 6.9 11.1 0.93 2.1 10.6 Ecosorb®b CX 7.0 11.1 0.93 2.4 11.1 Xerogel 1 7.2 11.2 0.96 2.8 10.9 Xerogel 4 6.9 10.5 0.94 2.2 9.7 Xerogel 6 7.1 10.4 0.90 2.7 10.4 Xerogel 5 7.1 10.6 0.94 2.8 11.3 Xerogel 2 7.2 11.5 0.97 2.7 11.2

These results showed that xerogels do not adversely affect baseline smoke rates; any differences are small and due to the variability of cigarettes and analysis.

The following table shows the percentage of reductions in vapor-phase smoke analytes for cigarettes that do not contain carbon in the filter.

Table % Reduced Smoke Analyzers Ecosorb® CX Xerogel 1 Xerogel 4 Xerogel 6 Xerogel 5 Xerogel 2 Acetaldehyde 27 9 35 thirty 24 25 Acetone 32 12 53 45 40 40 Acrolein 35 16 59 52 45 42 Butyraldehyde thirty 12 62 54 fifty fifty Crotonic aldehyde 35 fifteen 71 64 61 60 Formaldehyde 26 3 35 31 28 32 IEC 33 fifteen 63 55 51 51 Propionic Aldehyde 31 12 53 47 42 41 HCN fifteen 12 33 21 22 21 1,3-butadiene 25 13 48 45 42 36 Acrylonitrile 35 fifteen 58 58 fifty 40 Benzene 31 16 61 60 54 42 Isoprene 35 16 64 61 54 46 Toluene 26 12 65 67 62 36 Total analyte 29th 12 48 43 38 35

The results showed that all tested xerogels were effective in filtering smoke. All Xerogels 2, 4, 5, and 6 showed improvements over coconut charcoal. However, Xerogel 1 was not as effective as a control coconut coal sample, presumably due to the smaller mesopore volume and / or the smaller mesopore size.

Example 4. The synthesis of additional xerogels

Five additional xerogel samples having micropores and mesopores (in the case of one sample, small macropores) were prepared, as shown below.

300 g of resorcinol (Riedel-de Haen®, puriss. (98.5-100.5% purity) were mixed with 1375 g of deionized water, 442.25 g of formaldehyde (Fluka®, 37% in water) and 0.415 g of carbonate sodium (Fluka®, anhydrous) to give a clear solution. This solution was aged for 20 hours at room temperature, then 24 hours at 50 ° C and another 72 hours at 90 ° C. The polycondensate was crushed, introduced into 1500 ml of acetone and left for 3 days at room temperature, replacing the solvent every day, then the resulting product was dried at 50 ° C to give a red-brown, brittle solid, cat Roe rasp pulverized to obtain Granulate X with a particle size of 1-2 mm.

30.4 g of Granulate X was introduced into a quartz tube and placed in a drum furnace. The solid was heated to 250 ° C with a heating rate of 4 K / min in a stream of nitrogen and maintained at 250 ° C for one hour. The solid was then heated to 800 ° C at a rate of 4 K / min. During heating, the tube did not move, and after the solid reached 800 ° C, the rotor was turned on, and the solid was maintained at this temperature for 30 minutes in a nitrogen atmosphere. Then it was cooled to room temperature in a protective gas atmosphere. The resulting non-activated carbon Xerogel (186-02) was packaged in air.

38.74 g of Granulate X was introduced into a quartz tube and placed in a drum furnace. The solid was heated to 250 ° C with a heating rate of 4 K / min in a stream of nitrogen and maintained at 250 ° C for one hour. Then the solid was heated to 800 ° C at a speed of 4 K / min and maintained at this temperature for 30 minutes, after which it was heated to 880 ° C at a speed of 4 K / min. During heating, the tube did not move, and after the solid reached a temperature of 880 ° C, the rotor was turned on. The nitrogen stream was saturated with steam by sparging through boiling water, the front end of the tube was heated to prevent vapor condensation, and the solid was maintained at 880 ° C for 60 minutes in a saturated stream of nitrogen at 1.5 L / min. Then it was cooled to room temperature in an atmosphere of pure nitrogen. The resulting steam activated carbon Xerogel (186-0.4) was packaged in air.

Xerogels 186-08 and 186-09 were obtained in the same manner as Xerogel 186-04, however, starting from 48.35 g and 62.87 g of Granulate X, respectively, and increasing the steam activation time from 150 to 180 minutes, respectively.

Xerogel 008-10 was prepared using the following simplified conditions: 120.75 g of resorcinol (Riedel-de Haen®, puriss. (98.5-100.5% purity)) was mixed with 553 g of deionized water, 178.0 g formaldehyde (Fluka®, 37% in water) and 0.167 g of sodium carbonate (Fluka®, anhydrous) to give an anhydrous solution. This solution was introduced into the oven in a closed plastic bottle and kept there for 2 hours at 50 ° C followed by 14 hours at 90 ° C. After cooling to room temperature, the product was ground and dried at 50 ° C for four hours. Further grinding of the red-brown solid with a rasp gave Granulate Y having a maximum particle size of 3 mm.

300 g of Granulate Y was placed in a large quartz tube and introduced into a drum furnace. The solid was heated to 880 ° C with a heating rate of 4 K / min in a stream of nitrogen, then the rotor was turned on. The nitrogen stream was saturated with steam by bubbling through boiling water, the front end of the tube was heated to prevent vapor condensation, and the solid was maintained at 880 ° C for 80 minutes in a saturated stream of nitrogen. Then it was cooled to room temperature in an atmosphere of pure nitrogen. The resulting steam activated xerogel (Xerogel 008-10) was packaged in air.

All Xerogels 186-02, -04, -08, -0.9 and 008-10 took the form of transparent black granules.

Example 5. Xerogel Properties

Nitrogen adsorption isotherms were obtained at 77K and BJH analyzes of desorption curves were performed. The table below shows the properties of coal.

Table Try Surface Area (m ² / g) ^* Total pore volume (cm ³ / g) ^** The pore volume in micropores (cm ³ / g) Pore volume in mesopores and any macropores (cm ³ / g) The size range of mesopores and any macropores (nm) Pore size with a maximum in the size range of mesopores and macropores (nm) Ecosorb® CX 1000 0.50 0.50 0 - Xerogel 186-02 670 1.6 0.2 1.4 8-40 34 Xerogel 186-04 1100 2.1 0.4 1.7 6-50 34 Xerogel 008-10 1690 2.8 0.6 2.2 6-60 25 Xerogel 186-08 1830 3.0 0.7 2.3 8-45 25 Xerogel 186-09 1990 3.1 0.7 2.4 8-45 25 * Surface areas were measured using absorption at a relative pressure of P / P ₀ 0.2. ** Estimated by the amount of adsorbed N ₂ at a relative pressure P / P _{0 of} 0.98.

The structure of Xerogel 008-10 mesopores and macropores was also investigated using mercury porosimetry. The pore volume in the range of 6-100 nm was 2.2 cm ³ / g, which was in excellent agreement with the results obtained by nitrogen adsorption. In other words, large macropores were absent (which was not detected by nitrogen adsorption).

As an example, FIG. 4 shows a graph of the isotherm for Xerogel 008-10.

Example 6. The characteristic of the filter

Cigarettes were prepared and smoked in accordance with the method presented in example 3, but with the difference that Xerogels 186-02, -04, -08 and -09 were used, as in example 4, and coconut charcoal as a control, as in example 2. The results are presented in the following table.

Table % Reductions in the level of analytes smoke (comparison with an empty cavity) Carbon supplement Ecosorb® CX Xerogel 186-02 Xerogel 186-04 Xerogel 186-08 Xerogel 186-09 Acetaldehyde 23 38 46 61 56 Acetone 31 60 75 91 93 Acrolein 37 71 78 91 92 Butyraldehyde 36 69 84 95 96 Crotonic aldehyde 37 78 87 92 94 Formaldehyde 27 43 53 57 60 Methyl ethyl ketone 34 71 84 96 97 Propionic Aldehyde 34 64 78 93 94 HCN 38 fifty 62 63 61 1,3-butadiene fourteen 59 66 91 91 Acrylonitrile 25 68 72 88 88 Benzene 23 71 79 88 88 Isoprene 28 80 79 91 90 Toluene 17 53 53 54 52 The average value for the analyte 29th 63 71 82 82 # = limit of quantity

As can be seen from the data presented, these xerogels showed outstanding characteristics in smoke filtration compared to coal from coconut nuts and xerogels from example 1. Within these series, an increase in the total pore volume, micropore volume, mesopore volume and surface area corresponds to an improvement in smoke filtration.

Example 7. Filter characteristics in different smoking modes

Cigarettes containing 60 mg of Xerogel 008-10 or 60 mg of Ecosorb® CX were prepared in the same manner as in Example 3. Then the cigarettes were smoked in two different smoking modes. The first was a regular smoking regimen, including a 35 ml puff lasting 2 seconds every 60 seconds (35/2/60). The second was an intensive smoking regimen, i.e. 55 ml puff for 2 seconds every 30 seconds (55/2/30). The xerogel proposed in the invention showed better characteristics than charcoal from coconuts, as can be seen from the following table.

Table % Reductions in the level of analytes smoke (compared with an empty cavity) Carbon Filter Additive Ecosorb® CX Xerogel 008-10 Ecosorb® CX Xerogel 008-10 Smoking mode 35/2/60 35/2/60 55/2/30 55/2/30 Acetaldehyde 34 66 16 29th Acetone 44 92 28 60 Acrolein 48 93 35 63 Butyraldehyde 47 94 34 80 Crotonic aldehyde 56 95 ^# 46 93 Formaldehyde 36 60 42 68 Methyl ethyl ketone 49 96 36 84 Propionic Aldehyde 42 88 29th 56 HCN 44 84 25 54 1,3-butadiene twenty 83 22 51 Acrylonitrile 44 82 31 77 Benzene 43 85 29th 84 Isoprene 41 89 ^# 23 87 Toluene 35 60 ^# 26 66 ^# # = limit of quantity

Example 8. Change the properties of xerogel

60.0 g of resorcinol (puriss. (98.5-100.5% purity (Riedel-de Haen®, Catalog no. RdH 16101-1KG)) = 545 mmol, mixed in a plastic bottle (500 ml) with 275 g of deionized water, 88.45 g of a formaldehyde solution (Fluka®, 37%) = 1090 mmol and 83 mg of anhydrous sodium carbonate (Fluka®) = 0.78 mmol to obtain a clear solution.

The bottle was corked and placed in a 600 ml beaker, which was then placed in a convection oven at 90 ° C for 16 hours. Then the bottle was removed from the oven. Upon cooling to room temperature, a red-brown polycondensate was recovered from the bottle. The soft product was divided into large pieces using a spatula, placed on a flat aluminum pan (16 cm in diameter) and dried in a convection oven with a high air flow rate at 50 ° C for four hours.

The result was 267.9 g of wet, but already brittle material. The cooled material was crushed to a red-brown granulate (maximum particle size 3 mm) in a drum mill to obtain Granulate Z.

Example 8a

12.4 g of Granulate Z was introduced into a quartz tube and placed in a drum oven. The tube did not move during the heating phase.

The tube was purged with nitrogen and heated in a constant stream of nitrogen at a speed of 4 K / min from room temperature to 250 ° C and kept at this temperature for one hour. Then it was heated at a speed of 4 K / min to 800 ° C and, upon reaching this temperature, the furnace drum was turned on. The quartz tube rotated for 30 min in a stream of nitrogen. Then it was cooled to room temperature in a protective gas atmosphere. The resulting carbon xerogel was packaged in air. Product: 1.88 g (1 kg of resorcinol gives 677 g of carbon xerogel).

Analysis based on physical adsorption of N ₂

BET surface area: 659 m ² / g

Total pore volume according to the method of one glasses: 1.19 cm ³ / g

The ratio of micropore volume: mesopore volume (measured by physical adsorption of nitrogen): 1: 4.89

Mesopore diameter (measured by BJH desorption): maximum at 32 nm.

Example 8b

47.24 g of Granulate Z was placed in a quartz tube and placed in a drum furnace. In the heating phase, the tube did not move.

The tube was purged with nitrogen and heated in a constant stream of nitrogen at a speed of 4 K / min from room temperature to 880 ° C. Upon reaching this temperature, the oven drum was turned on. Then, protective nitrogen gas was bubbled through boiling water before being fed into the drum furnace. The gas inlet region of the quartz tube was heated to prevent condensation of water at that location. The quartz tube was rotated for 15 min at 880 ° C in an atmosphere of saturated nitrogen flow (1.5 l / min). Then the material was cooled to room temperature in an atmosphere of dry nitrogen. The resulting carbon xerogel was packaged in air. The process took 1.5 days from mixing the polymer solution to obtaining a carbon xerogel. Product: 5.73 g (1 kg of resorcinol gives 542 g of carbon xerogel).

Analysis based on physical adsorption of N ₂

BET surface area: 992 m ² / g

Total pore volume according to the method of one point: 1,65 cm ³ / g

The ratio of micropore volume: mesopore volume (measured by physical adsorption of nitrogen) 1: 3.80

Mesopore diameter (measured by BJH desorption): maximum at 33 nm.

Example 8c

51.1 g of Granulate Z was processed as in example 16, except that the material was activated for 30 minutes in an atmosphere of saturated nitrogen (preferably 15 minutes). Product: 5.38 g (1 kg of resorcinol gives 470 g of carbon xerogel).

Analysis based on physical adsorption of N ₂

BET surface area 1254 m ² / g

Total pore volume according to the method of one point: 1.93 cm ³ / g

The ratio of micropore volume: mesopore volume (measured by physical adsorption of nitrogen): 1: 3,55

Mesopore diameter (measured by BJH desorption): maximum at 33 nm.

Example 8g

51.04 g of Granulate Z was processed as in Example 86, except that the material was activated for 60 minutes at 880 ° C in saturated nitrogen (preferably 15 minutes). Product: 3.62 g (1 kg of resorcinol gives 317 g of coal xerogel).

Analysis based on physical adsorption of N ₂

BET surface area: 1720 m ² / g

Total volume according to the method of one point: 2.53 cm ³ / g

The ratio of micropore volume: mesopore volume (measured by physical adsorption of nitrogen): 1: 3.49.

Mesopore diameter (measured by BJH desorption): maximum at 24 nm.

Example 8d

Granulate Z was processed as in Example 86, except that the material was activated for 105 minutes at 880 ° C in saturated nitrogen (preferably 15 minutes). Product: 2.11 g (1 kg of resorcinol gives 180 g of carbon xerogel).

Analysis based on physical adsorption of N ₂

BET surface area: 2254 m ² / g

Total pore volume according to the method of one point: 3.23 cm ³ / g

The ratio of micropore volume: mesopore volume (measured by physical nitrogen adsorption): 1: 4.19

Mesopore diameter (measured by BJH desorption): maximum at 25 nm.

Example 9. Change the properties of xerogel

25.85 g of resorcinol (98% purity) = 230 mmol were mixed in a plastic bottle (250 ml) with 118.5 deionized water, 37.40 g of formaldehyde solution (Fluka®, 37%) = 461 mmol and 36 mg anhydrous sodium carbonate (Fluka®) = 0.34 mmol to give a clear solution.

The bottle was corked and placed in a beaker, then in a convection oven at 90 ° C for 16 hours. After that, the bottle was removed from the oven. After cooling to room temperature, the red-brown polycondensate was removed from the bottle. The soft product was divided into large pieces using a spatula, placed in an aluminum pan (16 cm in diameter) and dried in a convection oven with a high air flow rate at 50 ° C for 4 hours.

The resulting material weighed 99.4 g. The cooled material was ground to a red-brown granulate (maximum particle size 3 mm) in a drum mill.

39.05 g of granulate was introduced into a quartz tube and placed in a drum furnace. During heating, the tube did not move.

The tube was purged with nitrogen and in a constant stream of nitrogen was heated at a speed of 4 K / min from room temperature to 880 ° C. Upon reaching this temperature, the rotor of the furnace was turned on. Protective nitrogen was then bubbled through boiling water before being fed into the drum oven. The gas inlet region of the quartz tube was heated to prevent water condensation at this point. The quartz tube was rotated for 60 minutes at 880 ° C in a saturated stream of nitrogen (1.5 l / min). Then the material was cooled to room temperature in dry nitrogen. The resulting carbon xerogel was packaged in air. The resulting product was 3.12 g of black granulate.

Analysis based on physical sorption N ₂

BET surface area: 1843 m ² / g

Total pore volume according to the method of one point: 2.72 cm ³ / g

The ratio of micropore volume: mesopore volume (measured by physical adsorption of nitrogen): 1: 3.64

Mesopore diameter (measured by BJH desorption): maximum at 24 nm.

Example 10. Change the properties of xerogel

35.0 g of resorcinol (puriss. (Riedel-de Haen®, Catalog no. RdH 16101)) = 318 mmol were mixed in a plastic bottle (250 ml) with 24.5 g of deionized water, 51.65 g of formaldehyde solution (Fluka® , 37%) = 636 mmol and 66.5 mg of anhydrous sodium carbonate (Fluka® = 0.63 mmol) to give a clear solution.

The bottle was corked and placed in a beaker, then in a convection oven at 90 ° C for 16 hours. Then the bottle was removed from the oven. After cooling to room temperature, the red-brown polycondensate was removed from the bottle. The solid, transparent block was broken into large pieces using a hammer, placed on a flat aluminum pan (16 cm in diameter) and dried in a convection oven with a high air flow rate at 50 ° C for four hours.

The result was 59.23 g of product. The cooled material was crushed to a red-brown granulate (maximum particle size 3 mm) in a drum mill. 18.54 g of granulate was introduced into a quartz tube and placed in a drum furnace. During the heating phase, the tube did not move.

The tube was purged with nitrogen and heated in a constant stream of nitrogen at a speed of 4 K / min from room temperature to 880 ° C. Upon reaching this temperature, the rotor of the furnace was turned on. Protective nitrogen was then bubbled through boiling water before being fed into the drum oven. The gas inlet region of the quartz tube was heated to prevent condensation of water at that location. The quartz tube spun for 60 minutes at 880 ° C in a saturated stream of nitrogen (1.5 l / min). Then the material was cooled to room temperature in dry nitrogen. The resulting carbon xerogel was packaged in air. The resulting product weighed 3.62 g and was a black granulate (1 kg of resorcinol gives 330 g of coal xerogel).

Analysis based on physical sorption N ₂

BET surface area: 1628 m ² / g

Total pore volume according to the method of one point: 1,56 cm ³ / g

The ratio of micropore volume: mesopore volume (measured by physical adsorption of nitrogen): 1: 1.83

Mesopore diameter (measured by BJH desorption): maximum at 8 nm.

Claims (13)

1. A smoking article comprising a carbon dry gel, which is a xerogel, airgel and / or cryogel. 2. The smoking article of claim 1, wherein the carbon dry gel has a total pore volume, measured by nitrogen adsorption, of at least 0.5 cm ³ / g, of which at least 0.1 cm ³ / g is in mesopores. 3. The smoking article of claim 2, wherein the carbon dry gel has a total pore volume, measured by nitrogen adsorption, of at least 0.6, 0.7, 0.80, 0.85, 0.87, 0.89, 0.95, 0.98, 1.00, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0 or 3.1 cm ³ / g. 4. The smoking article of claim 2, wherein at least 0.2, 0.3, 0.4, 0.5, 0.55, 0.60, 0.65, 0.70, 0.75, 0.80, 0.85, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1, 9, 2.0, 2.1, 2.2, 2.3, or 2.4 cm ³ / g of the total pore volume of the carbon dry gel are mesopores when measured by nitrogen adsorption using the Barrett-Joyner-Halenda analysis ( BJH) on the nitrogen isotherm desorption curve. 5. The smoking article of claim 2, wherein at least 0.05, 0.10, 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, or 0.7 cm ³ / g of the total pore volume of the carbon dry gel falls on micropores when measured using a nitrogen adsorption isotherm. 6. A smoking article according to claim 2, in which the total volume of mesopores in the carbon dry gel is greater than the total volume of micropores. 7. The smoking article of claim 2, wherein the carbon dry gel has a pore size distribution in the range of 15-45 nm or 20-40 nm. 8. The smoking article of claim 2, wherein the BET surface area of the carbon dry gel is at least 500, 550, 600, 650, 700, 750, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800 or 1900 m ² / g. 9. The smoking article of claim 1, wherein the carbon dry gel is obtained by aqueous polycondensation of an aromatic alcohol with formaldehyde, followed by drying and carbonization. 10. The smoking article of claim 1, wherein the carbon dry gel is activated, optionally with steam and / or carbon dioxide. 11. The smoking article of claim 1, comprising a filter comprising a carbon dry gel. 12. A filter for a smoking article containing a carbon dry gel according to any one of claims 1 to 11. 13. The use of carbon dry gel according to any one of claims 1 to 11 for filtering smoke.

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